Millions of years ago, an ancient ape came to the plain from the rainforest and embarked on the evolutionary road full of blood and tears. Millions of years later, in the roar of rockets, human beings broke through the shackles of the earth’s gravity and deeply realized the vastness of the universe. But when human beings recover from this magnificent universe, a thought-provoking question arises: is there any life other than human beings in the universe?
In fact, although the earth is the only living planet known by human beings, there is not necessarily no other life in the vast universe. If we calculate by the ratio of 1:10, there are more than 100 billion stars in only one galaxy, then there are at least 10 billion stars in the whole galaxy, that is, the “Earth” where life may exist.
If the scope of the Milky way is too large, we can narrow it down to the solar system, because even in the solar system, the earth is not the only choice for life. For example, on Enceladus, there are three major elements that give birth to life: metabolizable energy, liquid water, and chemical elements such as nitrogen, oxygen, phosphorus, and carbon.
According to NASA research, under Europa’s thick ice layer, there is a huge water layer composed of almost the same liquid as the earth’s ocean, so it is likely that primitive life also exists. So, what kind of alien life are humans most likely to create first? Is it a simple life like cyanobacteria, or an intelligent life unrelated to human beings?
You may think that on planets inside or outside the solar system, the possibility of discovering simple life is higher than that of illusory aliens, but this may not be the case. People who study alien life should know that at present, there are two main directions for human beings to search for alien life: one is the familiar “alien civilization search plan”, the other is to use instrument observation to identify the “biological characteristics” in the earth’s atmosphere.
If we compare these two completely different search directions to two horse races, which of the two horse races do you think will reach the finish line first?
First, due to the limitation of the current technology level, human beings are unable to conduct field sampling. Therefore, even if “biological traces” are found in the atmosphere of a certain planet through the probe, it is difficult for us to draw such a conclusion that it is generated by life activities.
For example, in June 2019, NASA announced the discovery of a large amount of methane on Mars. This news immediately caused a sensation in the scientific community, because methane is a typical “biomarker”, most of the methane in the earth’s atmosphere is related to life activities. But in fact, this is not the first time that methane has been discovered on Mars, because Gail crater was discovered as early as 2013.
It’s just that curiosity was the only source of information at that time, so scientists haven’t really determined. This was not announced by scientists until June 2019, when they discovered it again in different places. Does the discovery of methane mean life? Although methane is the product of life activities, we still can not rule out that it is caused by the chemical reaction between rock and water.
Perhaps, the future “Mars soil remediation program” can provide us with an answer, but unless there are microorganisms or microbial fossils in Mars soil, the mystery of methane will haunt us for a long time.
Therefore, these potential alien civilizations are much more likely to be discovered than looking for these “biological marks”, because the radio waves and laser pulses emitted by them always travel outward at the speed of light. If we can find this regular signal in the cosmic noise, we can conclude their existence.
In recent years, with the progress and innovation of observation technology and equipment, as well as the extensive attention of the scientific community, SETI scientists estimate that in the ten years from 2022 to 2032, the possibility of recognizing and discovering the signals of alien civilization is at least three orders of magnitude higher than now.
In short, if there are alien civilizations in the universe, and they are actively looking for partners in the universe, there will be a breakthrough in their search in the next decade. It is worth noting that although the hope of discovering alien civilizations has grown with the passage of time, many scientists are still cautious, and even some scientists have warned that alien civilizations may not be in friendly contact with human beings. It may confirm another conjecture which may make people feel hopeless, that is, if the first discovery of human beings is alien simple life, rather than alien civilization.
That is to say, on the road of civilization development, there are strict “sieves” — the possibility of primitive life evolving into intelligent life is far lower than imagined. Even if intelligent life is successfully evolved, it will not be able to withstand the test of environmental deterioration, internal war, resource depletion and so on because of some bad qualities, and will be destroyed before showing itself to other civilizations in the universe great.